Filtering method and apparatus



March 22, 19331. F, W PADGETT v 2,111,7 20

FILTERING ME THOD AND APARATUS Filed March 13, 1956 'y flmw 1 Afro/iwer Patent'e Mar, 22, 1938.

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m'rnam'a ME'rnoD AND APriAaA'rUs Frederick W. Padgett; mam' Park, ra., assignozto Sun Oil Company, Philadelphia poration-of New Jersey ra., a cor- Appucation March 13, 1938, sensi No, 88,818

6 Claims.

The present invention relates to ,a method and apparatusvv for flltering. It is an` object of thisinvention to provide a. method and apparatus for filtering which is capable of 'continuous operation and capable of handling relative'ly large amounts of a mixture to be filtered It is a further object of this invention to provide a method and apparatus for filtering which.

will yield a relatively dry filter cake.

of apparatus e'mbodying my invention, and adapted for carrying out the process thereof.

Referring now to the drawing, the blend to be filtered, which may be alwax propaneoil slurry, is introduced through line and is distributed on a filter surface 2| which is in the form of a continuous belt. The filter surface 2| is continuously moving in the direction shown by the arrowsand passes between cooperating pairs w of rollers or wringers 22 and 23, 24 and 25, and 23 and 21. A continuous belt 23, which may either be impervious or a suitable filtering sur-- face in the form of a continuous belt, also passes i between the above mentioned cooperating pairs 25 of rollers or wringers. i

As shown in the drawing, each successive pair of wringers is spaced slightly closer together than the' previous pair, so that the pressure applied to the mixture being filtered'on filter surface 2| between filter' surface 2| and belt 28, is gradually increased, so that most of theliquid contained in the mixture is squeezed out and falls into tank 23 from which it is removed through 'valved line 30, so that'the fllter cake between filter surface 2| and belt 28 as they pass over roller 3| is relatively dry. The filter surface 2| and belt 28"then pass over rollers 32, 33, and 34 in tank 35 in which there is maintained a bath of suitable wash solvent. The filter cake between 4.0 fllter surface 2| and belt 28 is flexed and broken as the belts pass over the rollers in tank 35, so

i that the wash solvent is worked intothe cake and removes some of the oil which was not removed by the wringers over tank 29. The cake 45 between belts 2| and 23 is quite wet as it emerges from the bath ofsolvent in tank 35 andtherefore the two belts are passed .between cooperating wringers 36 and 31 which squeeze the most .of the liquid from the filter cake material, so 50 that the material between the two belts as it .enters a bath of liquid maintained in tank 33 is relatively dry. As the belts pass over 'rollers 33,

43, and 4| under the surface of a bath of suitable wash solvent maintain'edv in tank 33, the

i. wash solvrent'is worked into the filter vis .mate- The drawing is a diagrammatic representation z rial and washes any remaining oil therefrom. The filter cake material between the belts as they rise from 'the bath of liquid in tank 38 is relatively wet and therefore the belts are passed between the cooperating rollers and wringers 42 and 43 'which wring any liquid from the filter cake material `between the belts permitting it to fall back to tank 33 so that a relatively dry filter cake remains on belt 2| as it separates from belt 28.

Ordinarily, as the belts are separated the filter cake material will readily separate from them and then remain on the lower belt. Howevenif necessary, a scraper may be used to remove the material from the upper belt. As the belt or filter surface 2| passes over roller 44, the filter cake drops therefrom into wax tank 45, a suitablev scraper 43 being used to remove any cake adhering to surface 2|.

Asshown in the drawing, the 'wash liquid is introduced into tank 30 through line 41 and overfiows from tank 38 into tank 35, from which it is removed'through 'valved line 43, and any liquid which is squeezed from the filter cake by rollers 36 and 31| fails into tank 35 and that squeezed from the filter cake by rollers 32 and 43 falls into tank 38. However, it is of course possible to remove the wash solvent used in tank 33 before it overflows into tank 35 by any suitable means as a valved line 43 and introduce fresh Wash solvent into tank 35. It is also contemplated that the liquid squeezed from the filter cakeby rollers 36 and 31 may be collected separately as by a trough placed under these rollers, and that removed by rollers 42 and 43 may be also collected by a trough placed under these rollers. It is, of course, to be understood that suitable guide rolls such as 30, 5| and 52 will be provided for filter surface or belt 2|, and guide rolls such as 33, 54 and 35 will be provided for belt 23, some or all of these rolls being driven to impart the desired movement to the belts.

While I have herein specific embodiment of my invention, it is apparent that various apparatus shown and described herein without departing from the spirit of this invention or the .scope of the appended claims.`

What I claim and desire to-protect by Letters Patent is as follows:

1. A filter comprising a fiitering medium in the form of a continuous belt,'means for depositing a mixture wringer rolls between which said belt travels and which are adapted to press liquid from said material and ,form a 'filter cake on the belt surto be filtered on said belt,-

shown and described\a w changes may be made in the face. a tank adapted to contain a bath of Wash liquid, guide rolls in said tank over which said belt travels to cause it to enter a bath of liquid contained in said tank, wringer rolls between which said beit travels and which are adapted to press Wash liquid from said filter cake, and means beyond said last named rolls for removing said filter cake from said beit.

2. A filter comprising a pair of continuous belts lying one on the other, one. of which is a filter medium, means to introduce a mixture to be filtered to the space between said belts, Wringer `rolls between which said belts travel and which are adapted to press liquid from said material and form a filter cake between said belts, a tank adapted to contain a bath of a Wash liquid, guide rolls for said belts in said ta k to cause said belts to enter said bath, wringe rolls beyond` said tank and/ between which said belts travel and which are adapted to press Wash liquid from the filter cake between said belts. and means beyond said last named rolls to remove said filter cake from said filtering beit.

, 3. A filter comprising a pair of continuous belts lyingone on the other, one of which is a filter medium, means to introduce a mixture to be filtered to the space between said belts, wringer rolls betweenlwhich said belts travel and which are adapted to press liquid from said material and form a filter cake between said belts, a tank adapted to contain a bath of a Wash liquid, guide rolls for said belts in 'said tank to cause v said belts to enter said. bath, means for flexing said belts in said tank, wringer rolls beyond said tank and between which said belts travel and which are adapted to press Wash liquid from the filter cake between said belts, and means beyond said last. named rolls to remove said fil- ,ter cake from said flltering belt.

4. A filter comprising/a pair of continuous belts lying one on the other, one of which is a filter medium, means to introduce a mixture to be filtered to the space between said belts, wringer rolls between which said belts travel and which are adapted to press liquid from said material and form a filter cake between said belts, a series of tanks adapted to contain Wash liquid,

`guide rolls in each of said tanks to guide said belts into said tanks, Wringer rolls beyond each of said tanks and between which said belts travel and which are adapted to press Wash liquid from the filter cake therebetween, the last tank of said series having an inlet for Wash liquid, overflow means to flow Wash liquid from a succeeding tank of the series to the next preceding tank, the first tank of the series having a Wash liquid outiet, and means beyond the last of said Wringer rolls for removing filter cake from said filtering'belt.

5. The method of drying a mixture of a mathe dried ribbon and accumulating the dried material. a

6. A filter comprising two endless belts, one of which is a filtering medium; means to propel said belts and move their opposing surfaces toWard one another into fairly close approximation to thereby provide a mouth for the introduction between the belts of the mixture to be filtered; a plurality of pairs of Wringer rolls between which the belts successiveiy travel, the opposing driving faces of the rolls of a succeeding pair being spaced apartl a smaller distance than the driving faces of the rolls of a preceding pair to thereby propel the belts into closer approximation, press liquid from the mixture and form between the belts a filter cake still containing a liquid portion; means to thenceforward propel the belts in parallel relationship in said closer approximation and at the same time convey them through a Wash liquid and press 'therefrom the Wash liquid and substantially the remainder of the fraction of original liquid contained in the original mixture; and means to thenceforward separate the belts and scrape the cake from the filter medium beit.

FREDERICK W. PADGE'I'I'. 

